Musannaf Ibn Abi Shaybah 31063 — Book of the Judgments

Sulayman bin Yasar said: The matter of qasamah (oaths in an unresolved killing) is true, for the Prophet (peace and blessings be upon him) ruled by it. The Ansar were with the Messenger of Allah (peace and blessings be upon him) when a man from the Ansar went out. Then they left the Messenger of Allah (peace and blessings be upon him), and suddenly they saw their companion writhing, soaked in his blood. So they returned to the Messenger of Allah (peace and blessings be upon him) and said: "The Jews have killed our man," and they named a man from the Jews, but they had no evidence. So the Messenger of Allah (peace and blessings be upon him) said to them: "If two witnesses other than yourselves testify, I will hand him over to you." They had no evidence, so the Messenger of Allah (peace and blessings be upon him) said: "Swear fifty oaths and I will hand him over to you." The Ansar said: "We dislike swearing an oath over something we did not see." Then the Prophet (peace and blessings be upon him) wanted to take oaths from fifty of the Jews, but the Ansar said: "O Messenger of Allah (peace and blessings be upon him)! The Jews do not care about oaths. How can we accept their oaths? They will then go on to kill the rest of us." So the Messenger of Allah (peace and blessings be upon him) gave the blood money for the slain man from his own funds.